GREASE a 13x9-inch baking pan.
COMBINE marshmallows and corn syrup in a large saucepan. Cook over medium-low heat, stirring constantly, for 2 to 3 minutes or until marshmallows are melted. Remove from heat. Stir in cereal, pretzels and 2 cups Buncha Crunch.
PRESS cereal mixture into prepared baking pan. Sprinkle with remaining Buncha Crunch; press in lightly. Refrigerate for 20 minutes or until firm. Cut into bars.